1. Field of the Invention
The present invention relates to an X-ray analysis apparatus in which, by irradiating an X-ray to a sample and detecting a ray or a light radiating from the sample, such as X-ray and electrons, there is performed an element analysis or a composition analysis of the sample from that radiant ray. Especially, it relates to an X-ray analysis apparatus possessing an X-ray lens and a collimator.
2. Description of the Related Arts
For some time, as a method of performing the element analysis or the composition analysis of the sample, there is known a method of analyzing by irradiating the X-ray to the sample being examined from an X-ray tubular bulb, and detecting a fluorescent X-ray which is generated by an element contained in the sample which is excited by the irradiating X-ray, or the like by a detection system. Especially, there is a fluorescent X-ray analysis apparatus capable of specifying a contained amount of an object element by detecting the intensity of the fluorescent X-ray relating to the desired object element from a spectrum of the fluorescent X-ray.
Further, in the fluorescent X-ray analysis apparatus that is a conventional X-ray analysis apparatus, in the case of analyzing a microscopic region, the collimator having an opening of a size similar to the analyzed region is installed between the X-ray tubular bulb and the sample, and the microscopic part is analyzed by utilizing the X-rays passing through the opening. However, since most of the X-rays emitted from the X-ray tubular bulb are intercepted by the collimator, an intensity of the irradiated X-ray decreases, so that the X-ray analysis detection efficiency is bad.
Whereupon, in order to make the efficiency good, there is known a method of irradiating the microscopic region by focusing the irradiating X-rays, which previously were intercepted, by utilizing an X-ray lens such as polycapillary. (For example, refer to A. Bjeoumikhov et. al., “New generation of polycapillary lenses: manufacture and applications” X-ray Spectrom., 2003, 32, P. 172-178.)
FIG. 4 is a schematic view showing a constitution of the X-ray analysis apparatus by the prior art. It is constituted by an X-ray tubular bulb 1 generating the X-ray, the polycapillary used as an X-ray lens 2 focusing the X-ray, a sample S to be measured, and an energy dispersion type X-ray detector used as a detector 5 detecting the fluorescent X-ray.
The X-ray emitted from the X-ray tubular bulb 1 is focused onto the sample S by the X-ray lens 2, thereby exciting a constituent element in the sample S. The fluorescent X-ray emitted from the excited constituent element is measured in its energy by the detector 5 and, from the spectrum obtained by accumulating the measurement values, there is found the concentration of the constituent element in the sample S, or the thickness of a thin film on the sample surface.
Incidentally, although the conventional example shown in FIG. 4 is the fluorescent X-ray analysis apparatus, also in other X-ray analysis apparatuses having a mechanism measuring a phenomenon such as electrons, diffracted X-ray, or light which is generated by excitation with irradiating X-rays as the excitation source, it is known that the X-ray lens is similarly used for analysis of a microscopic part.
The X-ray lens is a device focusing the X-ray by utilizing a reflection, a scattering, an absorption or the like of the X-ray in the lens. However, in the case of X-rays of a high energy, efficiency of the reflection, the scattering or the absorption is low, and a probability of irradiating a portion other than a focal point on the sample due to deviation from a focused light path becomes high. In other words, in a method using the X-ray lens, focusing efficiency of the high energy X-ray is low, and there is increase in a halo component (distribution spread at the sample surface) faintly irradiating a focal point periphery and so out of focus. As a result, in a case where an excited X-ray of the high energy is necessary, it becomes impossible to neglect influence due to exciting simultaneously a region spreading to the focal point periphery, and accuracy as to which portion is being measured in an X-ray analysis is lost, so that a measurement precision becomes an issue.
Further, in the X-ray analysis, if a primary filter changing the energy distribution of the excited X-rays is used for the purpose of a microanalysis or the like, there is an issue that an influence of the halo component is intensified.